This invention relates generally to container systems, and more particularly to a container system used in the delivery of viscous fluids, such as lubricants.
The proper lubrication of mechanical systems requires the delivery of a suitable lubricant (e.g., grease) at regular intervals to various points of lubrication. A typical source of lubricant is a container system comprising a container filled with grease, and a follower in the container above the grease which moves up and down as the level of grease in the container rises and falls. Lubricant is pumped under pressure from the container to locations where the lubrication is needed.
Conventional systems have not been provided with suitable means for monitoring the level of grease in a container. By way of example, one such system uses a switch mounted on the lid of the container, a mass which rests on the follower in the container, and a flexible line connecting the mass to the switch. The length of the flexible line is such that when the follower descends to a level indicating that the container is substantially empty, the weight of the mass transfers from the follower to the flexible line and actuates the switch to indicate that the container needs to be refilled. However, until the switch is activated, there is no means for determining the level of fluid in the container, short of removing the lid. Further, when the container is refilled, there is no convenient means for determining when the container is full except by overflow of lubricant from the container, or by other means which are not convenient. In one prior art system, a mass is attached to the container lid by a flexible line to suspend the mass at a location inside the container corresponding to the desired maximum fill level. When the follower rises to the maximum fill level, it lifts the mass which activates a switch to stop the pump.
There is a need, therefore, for a system capable of sensing the level of viscous fluid (e.g., grease) in such containers not only when the fluid level is low but also at other levels so that the amount of fluid remaining in the container can be monitored on a continuous basis after the container is filled.